The invention relates to a color display tube comprising a neck having a base with a number of electrical leadthroughs, and an in-line electron gun being arranged in said neck, said electron gun comprising electrodes which are interconnected by two supporting elements of insulating material which extend on either side of and approximately parallel to the in-line plane, and comprising a number of supports which each form a connection between a supporting element and an electrical leadthrough and electrically contact the respective electrical leadthrough.
Such a color display tube is of the customary type, which is also referred to as the "in-line" type. In operation, an in-line electron gun generates three electron beams which extend in one plane, the so-called in-line plane. The elongated supporting elements are generally made from glass and are also referred to as "multiform" rods. In the manufacture of the color display tube, electrical leadthroughs are formed in a supporting plate (the assembly of supporting plate and electrical leadthroughs is also termed "base plate"), the electron gun is manufactured, the supports are secured to leadthroughs, so that the electron gun and the base plate are interconnected, and the electron gun is slid into the neck. Subsequently, the base plate is secured to the neck. The base plate which has been secured to the neck will hereinafter also be referred to as the base.
Ever higher demands are imposed on the positional accuracy of the electron gun in the neck of the colour display tube. A displacement or rotation of the electron gun relative to a mean position is disadvantageous. It has been found that, during sliding the electron gun into the neck, a displacement and/or rotation of the electron gun, and hence of the in-line plane, may occur. Said displacement and/or rotation causes a variation in the position of the electron gun, i.e. deviations in the position of the electron gun relative to the mean position occur.